The invention relates to an actuating mechanism for a motor vehicle, wherein a first element can be fastened to a vehicle; and a second element, which is connected to the first element so as to swivel around at least one axis of rotation, includes a mounting for a manipulatable member. The second element is connected to at least one adjustable element, which can be actuated by a drive between the first and the second element, and to at least one friction element, which rests against the first element.
DE-PS 30 26 561 discloses an actuating mechanism, for whose adjustment around two vertical axes there are adjustable elements in the form of racks, which are actuated by a drive, and for whose improved vibration damping there are friction elements in the form of spherical disk segments.
The known mirror adjustment exhibits the drawback that the adjustable elements are housed inside the drive housing and thus are located at a relatively short distance from the axes of rotation. Therefore, the controlling torque, exerted by the drive on the actuating mechanism, is also relatively low. Another drawback lies in the undefined friction forces, which are generated by the spherical dish segments. Since they are made of plastic, their elastic effect can decrease over the course of time.
Therefore, it is the object of the present invention to provide for the aforementioned class of rearview mirrors an especially high controlling torque and a frictional force that is as constant as possible over its life time, whereby the number of parts is kept to a minimum and the assembly is especially simple.
This problem is solved by the invention in that at least one friction element and one adjustable element form a one piece friction-adjustable element, which serves as the connecting element between the first and the second element, and the friction-adjustable element is under a tensile load.
Since the friction-adjustable elements are arranged on the outside of the first element, it is possible for the controlling torque to be especially high. Hence the large radius of friction is especially appropriate for damping the vibration and the holding force is very high. The tensile load further increases the positive effects, because zero tolerance is produced.
Preferably the friction-adjustable element consists of a metal band or a composite part with at least one toothed region, since this design makes it especially easy to manufacture, and it exhibits adequate strength. The teeth can be cut into the metal band by perforation, drawing or punching. The friction-adjustable element can also be designed as an engineering plastic part, especially if the quality of the teeth must meet special requirements. Preferably at least one friction-adjustable element is connected to the second element at connecting points.
A second solution to the problem includes a chain with a number of links forms the adjustable element and the friction element, wherein the chain is under tensile stress. The chain exhibits the advantage that it can be moved in all directions, thus following the movements of an adjustable element in all directions.
Preferably the drive engages in or between the chain links in order to produce a drive coupling, thus eliminating the need of impressing separate teeth. To swivel the second element around two axes of rotation that are vertical to each other, there are two friction-adjustable elements or two chains.
A preferred improvement of the invention embodies the feature that the two friction-adjustable elements can be driven independently of each other. Each friction-adjustable element is connected to the second element at at least two of the connecting points. When using two connecting points per friction-adjustable element, one connecting point of the second element with the first friction-adjustable element is followed by a connecting point of the second element with the second friction-adjustable element, whereby the connecting points are spaced uniformly apart at an angle of 90xc2x0 with respect to an intersection of both axes of rotation. Each friction-adjustable element encloses the first element; and the friction-adjustable elements are guided at least partially in or at the first element.
Since the friction-adjustable elements can be driven independently of each other, the teeth are easy to design because there are no or only few nonaxial movements. The first element can be enclosed by the two connecting points of the friction-adjustable elements with the second element with the result that the second element is held securely at the first element. To lock the friction-adjustable elements in position, guides are provided in or at the first element.
Since the two friction-adjustable elements cross at one point, it is necessary to form the first element in such a manner that the two friction-adjustable elements do not impede one another. The same effect can be achieved through a suitable design of the friction-adjustable elements. In particular the use of thin metal bands eliminates impedance between the two friction-adjustable elements, even if they slide over one another. Thus the first element is especially easy to design. The two friction-adjustable elements can also be in essence uniformly spaced apart relative to the intersection of the axes of rotation.
When using large friction-adjustable elements, it may become necessary to arrange the two friction-adjustable elements on different rails and at least partially at varying distances from the intersecting point of the axes of rotation so that they do not impede each other.
It is especially advantageous to allow tensile forces to act on the friction-adjustable elements not only when standing still but also in operation, thus ruling out any play between the first and the second element. The tensile forces can be achieved, for example, by designing at least one friction-adjustable element with a springy region. In particular it is desirable to design the springy region as a wave, since the desired maximum range of the spring can be accurately set. In the assembled state, the springy region is completely stretched in order to exclude as much as possible dead travel in operation.
According to another important feature of the invention, the second element is designed essentially rigid, thus significantly suppressing vibrations of the manipulatable member.
An improvement of the invention provides the second element with an annular rim/an annular wall, which has a special reinforcing effect on the second element.
On this rim/wall are moulded the connecting points to the at least one friction-adjustable element. Thus the adjusting forces are transferred optimally to the entire second element.
According to an especially easy to assemble improvement of the invention the connecting points are designed in the form of a catch projecting from the ring interior. Moreover, these catches have the shape of circular segments with the result that the center points of the circular segments can lie on the axes of rotation. Thus the friction-adjustable elements can make swivel movements and large torques can be transferred.
Since the second element has spring members, to which the connecting points between the friction-adjustable elements and the second element can be moulded, the friction-adjustable element can be designed without a springy region. The spring members can be simply designed by affixing a slotted recess in the second element.
At least one friction-adjustable element is hinged to the second element, thus eliminating the need for the friction-adjustable element to be provided with an arched toothing. To reduce the weight of the second element and make it easy to produce, yet ensure adequate strength, the second element can be designed as an aluminum drawn part, an aluminum cast part or a magnesium diecast part.
A design with especially few components is achieved in that there are no attachment means between the first and second element. This is possible because the friction-adjustable elements suffice as attachment elements. To ensure that the first and the second element lock there is a spherical cap provided with guides and grooves. This locking mechanism enables a reliable and accurate positioning.
Expediently the first element includes recesses, by means of which gear members of the drive can engage with the one piece friction-adjustable elements.
Owing to the special geometric features for adjusting the adjustable element around two axes of rotation that are perpendicular to each other, it may be necessary for specific settings to design the friction-adjusting members flexibly at a right angle to the adjustment direction so that the friction-adjustable elements can be fixed with the second element on the side of the connecting points. However, in the case of a rigid design, the friction-adjustable elements must be able to escape sideways in the connecting points.
Owing to the geometric features, the angles of the friction-adjustable elements in the extreme positions of the second element can deviate slightly from 90xc2x0. Therefore, it may or may not be necessary in a rigid design that at least one friction-adjustable element has the option of escaping sideways with the second element at at least one connecting point.
In the case of anointed connection of the friction-adjustable element with the second element, it is expedient for the friction-adjustable elements to be guided in guides on the side of the first element. Preferably there are guides on both sides.
If at least one of the friction-adjustable elements is positioned in the guides so that they can be moved lengthwise with little or only very little play sidewalks, this configuration then ensures locking between the first element and the second element. An additional locking mechanism is thus superfluous. In order not to limit the mobility of the second element with respect to the first element, at least one friction-adjustable element can be moved longitudinally in the guides and can be moved slightly sideways. Hence, the guides can be designed at least in part as a groove.
The toothed region of at least the friction-adjustable element can face the first element or be arranged at approximately 90xc2x0 thereto. Thus different types of gear designs can be used. It is also possible to have at lest one part of a friction-adjustable element, which carries the toothed region, project into the interior of the first element.
To prevent the friction-adjustable element and the gear member from disengaging under a large load or when actuating the drive at an end stop of the mirror, at least one friction-adjustable element can be braced with a bracing member at least in the region of engagement with the gear member.
If, on the other hand, such a bracing member is omitted, the gear member can possibly jump at a high load into the toothed region of the friction-adjusting member. Thus an additional overload coupling is superfluous.
The friction-adjustable element can be braced in that a bracing element reaches behind it at least partially. In this respect the bracing element can also be designed as a snap connection. This design facilitates the assembly of the friction-adjustable element, especially if the snap connection is designed in the shape of snap hooks. The guide and/or the snap connection is/are designed as one piece with the first element. The bracing members are designed preferably as one piece with the first element or as one piece with the second element.
Another possibility to simplify the assembly is to connect the bracing member to the first element with a film hinge. In this respect the bracing member is held by a snap connection in its final assembled position.
To facilitate the assembly of the friction-adjustable elements, a spring element can be arranged between the first element and the second element. In the simplest case this spring element is designed as one piece with the first element or the second element, but a spring element can also be provided. In this case the spring element endeavors to push the second element away from the first element; and at least one friction-adjustable element holds the second element against the spring action of the spring element at the first element. During assembly of the friction-adjustable element, the second element can be forced against the spring action against the first element by means of an assembly tool. In this manner it is easier to connect the ends of the friction-adjustable element to the projecting catch on the second element. Following assembly, the spring provides for zero tolerance between the first and the second element and between the friction-adjustable element and the first as well as the second element. A similar simplified assembly can also be achieved if a friction-adjustable element is provided with a springy region, or if the second element is designed as a spring member in the region of the connecting points.
To design the actuating mechanism with memory, it is proposed that the wall of the first element be provided with recesses, by means of which at least one position finder can be coupled with the friction-adjustable elements. In this case one part of the position finder can be arranged inside the first element; and a second part can be permanently connected to a friction-adjustable element, with the result that a connection can be produced between the two parts by means of the wall of the first element.
Another possibility of assembling a memory device is to retrofit the position finder on the first element from the outside and to connect it both mechanically and electrically to the first element. Thus a modular design is produced that permits a smaller inventory of different types of drives or drive parts.
The possibility of realizing the electrical connection between the position finder and the mirror attachments by means of sheet metal guides has proven to be especially advantageous. In this case the sheet metal guides can be formed by injection in the first element.
The actuating mechanism of the invention is especially suitable for actuating a rearview mirror of a motor vehicle.